I've purchased both the Beach and Niles...prefer the Beach by far! Why? I've got wide feet and the Beach fit my wide puppies better. I ended up giving the Niles to my sister, who had grimaced when she saw my Beach, but once she tried on the Niles she was sold...kept walking around the room..."these are comfortable....these are comfortable".
Actually, the Cayman and the Beach are the exact same shoe with the only difference being that the Cayman are a "more true size" running in whole sizes while the Beach are S, M, L, XL. I have the M which says women's size 8 - 9. Also, on the website they list a model, Aspen, which used to have an equal style called "highland", but I'm not sure if the two styles are different and if so how. Also, most retailers will have the Beach style, unless they are a larger retailer. To find a store near you, just go to the website...
www.crocs.com
Hope this helps!